TEREBRATUL1D-<E. 307 



Geological Distribution of the Families of Brachiopods. 











3 

















d 



a 



Q 



i 



u 



in 



1 



■3 

 o 



a 



a 







3 

 o 



1 





s 



Arthropomata. 





Terebratuliclse, 





* 



* 



* 



* 



* 



* 



* 



* 



* 



ThecideidiB, . . 















V 



y 



* 



* 



* 



* 



* 



Stringocephalidae, 













* 

















Rhjaicbonellidae, . 











* 



* 



* 



* 



* 



* 



* 



* 



* 



Atrvpidse, . . . 











* 



* 



V 



:'' 













Spiriferidse, . . . 











* 



* 



* 



* 



* 



* 









Koninckinidae, . . 













* 







* 



* 









Strophomenidse, . 









* 



* 



* 



* 



* 



* 



* 









Ptoductidse, . . 











* 



* 



* 



* 













Lyopomata. 























Craniadfe, 





* 



* 



* 



* 



* 



* 



* 



* 



* 



Trimerellidae, 





* 



















Discinidse, 



* 



* 



* 



* 



* 



* 



* 



* 



* 



* 



Obolidse, 



* 



* 



















Lingulidse, 



* 



* 



* 



* 



* 



* 



* 



* 



* 



* 



Order ARTHROPOMATA. 

 (Apygia, Bronn. Articulata, Huxley.) 

 Shell testaceous, articulated by hinge-teeth, with usually an 

 internal skeleton-like testaceous process. Animal destitute of 

 an anal aperture (Clistenterata, King). 



Family TEREBRATULIDvE. 



Shell minutely punctate ; usually round or oval, smooth or 

 striated ; ventral valve with a prominent beak, perforated near 

 or at the apex, and attached by a peduncle passing through the 

 perforation, or by a portion of the valve itself; hinge with two 

 curved teeth ; dorsal valve with a depressed umbo, a prominent 

 cardinal process between the dental sockets, and a slender shelly 

 loop. 



Animal attached by a pedicel, or by the ventral valve ; oral 

 arms united to each other by a membrane, variqusly folded ; 

 sometimes spiral at their extremities. 



